Nevertheless, for the arguments of Ref. [1]} to hold, it is sufficient that the Thakurta metric is sourced by a stress-energy tensor that contains a radial energy flux into the BH, which supports its mass growth with the accretion rateBy accretion we mean \(\dot{M} > 0\) . In general relativity, this implies an influx of energy (as opposed to a spontaneous generation of mass as in, e.g. , the steady-state universe).
\(\dot{M} = H M.\) 
